Implement Chop

.github/workflows/build.yml

@@ -43,8 +43,8 @@ jobs:
 
       - name: Pull odgi container
         run: |
-          docker pull quay.io/biocontainers/odgi:0.8.3--py310h6cc9453_0
-          docker tag quay.io/biocontainers/odgi:0.8.3--py310h6cc9453_0 odgi
+          docker pull quay.io/biocontainers/odgi:0.8.6--py310hdf79db3_1
+          docker tag quay.io/biocontainers/odgi:0.8.6--py310hdf79db3_1 odgi
       - name: Install odgi alias
         run: |
           mkdir -p $HOME/.local/bin
@@ -76,6 +76,32 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions-rust-lang/setup-rust-toolchain@v1
 
+      # Install slow-odgi.
+      - uses: actions/cache@v4
+        id: cache-uv
+        with:
+          path: ~/.cache/uv
+          key: ${{ runner.os }}-python-${{ matrix.python-version }}-uv
+      - name: Create and activate virtualenv with uv
+        run: |
+          curl -LsSf https://astral.sh/uv/install.sh | sh
+          uv venv
+          echo "VIRTUAL_ENV=.venv" >> $GITHUB_ENV
+          echo "$PWD/.venv/bin" >> $GITHUB_PATH
+      - name: Install Python tools
+        run: uv pip install -r requirements.txt
+
+      # Install odgi
+      - name: Pull odgi container
+        run: |
+          docker pull quay.io/biocontainers/odgi:0.8.6--py310hdf79db3_1
+          docker tag quay.io/biocontainers/odgi:0.8.6--py310hdf79db3_1 odgi
+      - name: Install odgi alias
+        run: |
+          mkdir -p $HOME/.local/bin
+          cp .github/odgi.sh $HOME/.local/bin/odgi
+          chmod a+x $HOME/.local/bin/odgi
+
       # Install Turnt.
       - uses: actions/setup-python@v5
         with:

Makefile

@@ -9,14 +9,29 @@ endif
 tests/%.gfa:
 	curl -Lo ./$@ $(GFA_URL)/$*.gfa
 
+tests/%.og: tests/%.gfa
+	odgi build -g $< -o $@
+
 .PHONY: fetch
 fetch: $(TEST_FILES:%=tests/%.gfa)
 
+fetch-og: $(TEST_FILES:%=tests/%.og)
+
 .PHONY: test-slow-odgi
 test-slow-odgi: fetch
 	make -C slow_odgi test
 
 .PHONY: test-flatgfa
-test-flatgfa:
+test-flatgfa: fetch
 	cd flatgfa ; cargo build
+
 	turnt -e flatgfa_mem -e flatgfa_file -e flatgfa_file_inplace tests/*.gfa
+
+	-turnt --save -v -e chop_oracle_fgfa tests/*.gfa
+	turnt -v -e flatgfa_chop tests/*.gfa
+
+	-turnt --save -v -e odgi_depth tests/*.gfa
+	turnt -v -e flatgfa_depth tests/*.gfa
+
+clean:
+	-rm tests/*.flatgfa tests/*.inplace.flatgfa tests/*.chop tests/*.depth tests/*.gfa tests/*.og

bench/bench.py

@@ -72,7 +72,6 @@ def hyperfine(cmds):
             "hyperfine",
             "--export-json",
             tmp.name,
-            "--shell=none",
             "--warmup=1",
             "--min-runs=3",
             "--max-runs=16",
@@ -223,7 +222,7 @@ def run_bench(graph_set, mode, tools, out_csv):
         for tool in tools:
             assert tool in runner.config["modes"][mode]["cmd"], f"unknown tool {tool}"
     else:
-        # Use all supported tools by deefault.
+        # Use all supported tools by default.
         tools = list(runner.config["modes"][mode]["cmd"].keys())
 
     # Fetch all the graphs and convert them to both odgi and FlatGFA.

bench/config.toml

@@ -24,9 +24,14 @@ convert = false
 cmd.flatgfa = '{fgfa} -I {files[gfa]}'
 cmd.slow_odgi = '{slow_odgi} norm {files[gfa]}'
 cmd.odgi = '{odgi} view -g -i {files[gfa]}'
-cmd.gfatools = "{gfatools} view {files[gfa]}"
+cmd.gfatools = '{gfatools} view {files[gfa]}'
 
 [modes.depth]
 cmd.flatgfa = '{fgfa} -i {files[flatgfa]} depth'
 cmd.odgi = '{odgi} depth -i {files[og]} -d'
-cmd.slow_odgi = '{slow_odgi} depth {files[gfa]}'
+cmd.slow_odgi = '{slow_odgi} depth {files[gfa]}'
+
+[modes.chop]
+cmd.flatgfa = '{fgfa} -i {files[flatgfa]} chop -c 3'
+cmd.odgi = '{odgi} chop -i {files[og]} -c 3 -o -'
+cmd.slow_odgi = '{slow_odgi} chop {files[gfa]} -n 3'

flatgfa/src/cmds.rs

@@ -1,5 +1,6 @@
-use crate::flatgfa::{self, Handle, Segment};
-use crate::pool::{self, Id, Store};
+use crate::flatgfa::{self, Handle, Segment, Path, Orientation, Link};
+use crate::pool::{self, Id, Span, Store};
+use crate::{GFAStore, HeapFamily};
 use argh::FromArgs;
 use std::collections::{HashMap, HashSet};
 
@@ -201,7 +202,7 @@ impl<'a> SubgraphBuilder<'a> {
 
     /// Add a single subpath from the given path to the subgraph.
     fn include_subpath(&mut self, path: &flatgfa::Path, start: &SubpathStart, end_pos: usize) {
-        let steps = pool::Span::new(start.step, self.store.steps.next_id());
+        let steps = pool::Span::new(start.step, self.store.steps.next_id()); // why the next id?
         let name = format!("{}:{}-{}", self.old.get_path_name(path), start.pos, end_pos);
         self.store
             .add_path(name.as_bytes(), steps, std::iter::empty());
@@ -245,6 +246,7 @@ impl<'a> SubgraphBuilder<'a> {
 
     /// Translate a handle from the source graph to this subgraph.
     fn tr_handle(&self, old_handle: flatgfa::Handle) -> flatgfa::Handle {
+        // TODO: is this just generating the handle or should we add it to the new graph?
         flatgfa::Handle::new(self.seg_map[&old_handle.segment()], old_handle.orient())
     }
 
@@ -318,3 +320,176 @@ pub fn depth(gfa: &flatgfa::FlatGFA) {
         );
     }
 }
+
+
+/// chop the segments in a graph into sizes of N or smaller
+#[derive(FromArgs, PartialEq, Debug)]
+#[argh(subcommand, name = "chop")]
+pub struct Chop {
+    /// maximimum segment size.
+    // Use c in keeping with odgi convention
+    #[argh(option, short = 'c')]
+    c: usize,
+
+    /// compute new links
+    #[argh(switch, short = 'l')]
+    l: bool,
+}
+
+/// Chop a graph into segments of size no larger than c
+/// By default, compact node ids
+/// CIGAR strings, links, and optional Segment data are invalidated by chop
+/// Generates a new graph, rather than modifying the old one in place
+pub fn chop<'a>(
+    gfa: &'a flatgfa::FlatGFA<'a>,
+    args: Chop,
+) -> Result<flatgfa::HeapGFAStore, &'static str> {
+
+    let mut flat = flatgfa::HeapGFAStore::default();        
+
+    // when segment S is chopped into segments S1 through S2 (exclusive), 
+    // seg_map[S.name] = Span(Id(S1.name), Id(S2.name)). If S is not chopped: S=S1, S2.name = S1.name+1
+    let mut seg_map: Vec<Span<Segment>> = Vec::new();
+    // The smallest id (>0) which does not already belong to a segment in `flat`
+    let mut max_node_id = 1;
+
+    fn link_forward(flat: &mut GFAStore<'static, HeapFamily>, span: &Span<Segment>) {
+        // Link segments spanned by `span` from head to tail
+        let overlap = Span::new_empty();
+        flat.add_links(
+            (span.start.index()..span.end.index()-1).map(|idx| {
+                Link {
+                    from: Handle::new(Id::new(idx), Orientation::Forward),
+                    to: Handle::new(Id::new(idx+1), Orientation::Forward),
+                    overlap
+                }
+            })
+        );
+    }
+
+    // Add new, chopped segments
+    for seg in gfa.segs.all().iter() {
+        let len = seg.len();
+        if len <= args.c {
+            // Leave the segment as is
+            let id = flat.segs.add(Segment {
+                name: max_node_id,
+                seq: seg.seq,
+                optional: Span::new_empty()
+                // TODO: Optional data may stay valid when seg not chopped?
+            });
+            max_node_id += 1;
+            seg_map.push(Span::new(id, flat.segs.next_id()));
+        }
+        else {
+            let seq_end = seg.seq.end;
+            let mut offset = seg.seq.start.index();
+            let segs_start = flat.segs.next_id();
+            // Could also generate end_id by setting it equal to the start_id and
+            // updating it for each segment that is added - only benefits us if we 
+            // don't unroll the last iteration of this loop
+            while offset < seq_end.index() - args.c {
+                // Generate a new segment of length c
+                flat.segs.add(Segment {
+                    name: max_node_id,
+                    seq: Span::new(Id::new(offset), Id::new(offset + args.c)),
+                    optional: Span::new_empty()
+                });
+                offset += args.c;
+                max_node_id += 1;
+            }
+            // Generate the last segment
+            flat.segs.add(Segment {
+                    name: max_node_id,
+                    seq: Span::new(Id::new(offset), seq_end),
+                    optional: Span::new_empty()
+            });
+            max_node_id += 1;
+            let new_seg_span = Span::new(segs_start, flat.segs.next_id());
+            seg_map.push(new_seg_span);
+            if args.l {
+                link_forward(&mut flat, &new_seg_span);
+            }
+        }
+    }
+
+    // For each path, add updated handles. Then add the updated path
+    for path in gfa.paths.all().iter() {
+        let path_start = flat.steps.next_id();
+        let mut path_end = flat.steps.next_id();
+        // Generate the new handles
+        // Tentative to-do: see if it is faster to read Id from segs than to re-generate it?
+        for step in gfa.get_path_steps(path) {
+            let range = {
+                let span = seg_map[step.segment().index()];
+                std::ops::Range::from(span)
+            };
+            match step.orient() {
+                Orientation::Forward => {
+                    // In this builder, Id.index() == seg.name - 1 for all seg
+                    path_end = flat.add_steps(
+                        range.map(|idx| {
+                            Handle::new(
+                                Id::new(idx),
+                                Orientation::Forward
+                            )
+                        })
+                    ).end;
+                },
+                Orientation::Backward => {
+                    path_end = flat.add_steps(
+                        range.rev().map(|idx| {
+                            Handle::new(
+                                Id::new(idx),
+                                Orientation::Backward
+                            )
+                        })
+                    ).end;
+                }
+            }
+        }
+
+        // Add the updated path
+        flat.paths.add(Path{
+            name: path.name,
+            steps: Span::new(path_start, path_end),
+            overlaps: Span::new_empty()
+        });
+    }
+
+    // If the 'l' flag is specified, compute the links in the new graph
+    if args.l {
+        // For each link in the old graph, from handle A -> B:
+        //      Add a link from
+        //          (A.forward ? (A.end, forward) : (A.begin, backwards))
+        //          -> (B.forward ? (B.begin, forward) : (B.end ? backwards))
+
+        for link in gfa.links.all().iter() {
+            let new_from = {
+                let old_from = link.from;
+                let chopped_segs = seg_map[old_from.segment().index()];
+                let seg_id = match old_from.orient() {
+                    Orientation::Forward => chopped_segs.end - 1,
+                    Orientation::Backward => chopped_segs.start
+                };
+                Handle::new(seg_id, old_from.orient())
+            };
+            let new_to = {
+                let old_to = link.to;
+                let chopped_segs = seg_map[old_to.segment().index()];
+                let seg_id = match old_to.orient() {
+                    Orientation::Forward => chopped_segs.start, 
+                    Orientation::Backward => chopped_segs.end - 1,
+                };
+                Handle::new(seg_id, old_to.orient())
+            };
+            flat.add_link(
+                new_from,
+                new_to,
+                vec![]
+            );
+        }
+    }
+
+    Ok(flat)
+}

flatgfa/src/flatgfa.rs

@@ -101,6 +101,12 @@ pub struct Path {
     pub overlaps: Span<Span<AlignOp>>,
 }
 
+impl Path {
+    pub fn step_count(&self) -> usize {
+        self.steps.end.index() - self.steps.start.index()
+    }
+}
+
 /// An allowed edge between two oriented segments.
 #[derive(Debug, FromBytes, FromZeroes, AsBytes, Clone, Copy)]
 #[repr(packed)]
@@ -265,6 +271,10 @@ impl<'a> FlatGFA<'a> {
         self.name_data[path.name].as_ref()
     }
 
+    pub fn get_path_steps(&self, path: &Path) -> impl Iterator<Item = &Handle> {
+        self.steps[path.steps].iter()
+    }
+
     /// Get a handle's associated segment.
     pub fn get_handle_seg(&self, handle: Handle) -> &Segment {
         &self.segs[handle.segment()]
@@ -277,8 +287,8 @@ impl<'a> FlatGFA<'a> {
 
     /// Look up a CIGAR alignment.
     pub fn get_alignment(&self, overlap: Span<AlignOp>) -> Alignment {
-        Alignment {
-            ops: &self.alignment[overlap],
+        Alignment { 
+            ops: &self.alignment[overlap]
         }
     }
 
@@ -353,6 +363,11 @@ impl<'a, P: StoreFamily<'a>> GFAStore<'a, P> {
         self.steps.add(step)
     }
 
+    /// Add a sequence of links.
+    pub fn add_links(&mut self, links: impl Iterator<Item = Link>) -> Span<Link> {
+        self.links.add_iter(links)
+    }
+
     /// Add a link between two (oriented) segments.
     pub fn add_link(&mut self, from: Handle, to: Handle, overlap: Vec<AlignOp>) -> Id<Link> {
         self.links.add(Link {